Single phase to 3 phase question

[DiddyFA]

Hi guys I am an approved electrician but never come across this before. A customer wants to upgrade his single phase to 3 phase 100 amp supply.
The single phase supply that is there supplies his shop and upstairs flat that is privately owned.
New supply will feed a tp&n board as well as original shop board and original flat fuse board. I am concerned about metering arrangements ect. Can I run a 4 core armour to feed shop board (they are in another room from where new supply will be) Is that ok ?
TP&N board will only supply two three-phase sunbeds...easy doings as its just the TPN isolator - new TPN board and then a couple of tp&n isolators adjacent to sunbeds fed by suitably sized armour.

So Q1 was Can you supply two boards same phase from 1 4 core cable and use some type of ryefield board to split the 4 core into 2 core and earth?
Q2 is can uk power networks complete their work and reinstall meters in one visit or does the dno need to come and move the meters?

To be honest, I am going to pass this on to another as it comes at a busy time for me with family work and holiday stuff all coming up...but I DO want to know for future reference. I have done all sorts of sub mains ect on new builds but never in the situation where existing connections need removing and never with a 3rd party (upstairs flat in this case)...just wondering what you guys would do to leave an install such as the above in a "connection ready" state so that the uk power networks can do their thing.

As a little aside this client got a price for uk power network just over 1 year ago for installing the new 3 phase 100 amp supply...he got quoted just shy of £3k.....They didn't do anything for a year and then called uk power network to see if they could proceed and how much difference in cost.....Forwarded to their new department as quote no longer valid and this new department deals with all 3 phase supplies....new cost £12k....lol. Most of that is for digging up pavement outside the shop.

 

[ProDave]

You seem to be over complicating it.

New 3 phase supply to new 3 phase board.

3 phase sun beds fed from 3 pole mcb's / rcbo's as approporiate

1 pole MCB to feed existing shop CU

1 pole MCB to feed existing flat CU

Both 1 phase loads from a different phase.

Not sure why you think you need 4 core cable to feed existing CU's?

 

[DiddyFA]

The existing flat cuand existing shop cu are right next to each other in another room 15 meters away from the new db and incomer ect. I was wondering if i could take a 4 core from main new db to feed exisiting shop cu and exisitng flat cu....like i said this is obviously what was once a shop with an upstairs which has been converted..so the situated flats db right next to shops db....at back of shop...new stuff is going in at the front of shop.....thats's what i was going on about when i said could i then split the 4 core cable to feed both cu's ? Both cu's will be on the same phase......In my head, I think I "should" run two separate 3 core armoured 1 for each board. ....Was just wondering if you "could do this and split it somehow in old db cupboard.

The other question was just about metering arrangements...will ukpower just reconnect the existing meters and install a 3 phase meter on the same day ? Like i said just nosey as I REALLY AM NOT DOING THIS...I have done every skill involved in the job...i have done fuse rooms ect so have experience in doing this type of stuff but have never designed it for myself. Also have seen uk power networks in action before and the slightest thing they don't like or not ready they are off like whippets lol.

 

[Sharpend]

Do you propose to meter the shop and flats separately or combined ? 

 

[DiddyFA]

They are already metered separately...again both meters presently in the cupboard .....metering will be at front of shop beside new incomer ect.